No North Coast October-May total reached its 1991-2020 mean after 34 dry starts in 1901-2025

We tested spring precipitation recovery after dry October-February seasons in seven California climate divisions during 1901-2025. Dry means at most 80% of the 1991-2020 early-season mean. Recovery means that October-May precipitation reaches its 1991-2020 mean. North Coast had no recovery in 34 dry cases. Pairing each dry early season with all 125 historical springs gave a recovery rate of 1.58%. The observed minus independent difference was -1.58 percentage points. A circular-shift reference test gave a two-sided probability of 0.616. Thus, the record does not show a clear departure from independent seasonal pairing. A block bootstrap interval excluded zero, but resampling cannot create a recovery in a zero-event sample. That interval must not be used as evidence for suppressed recovery. Four divisions had no recovery; South Coast had six recoveries in 56 dry cases. The data support rare recovery under this strict precipitation definition. They do not measure water supply or prove a physical cause. The package gives fixed source lines, annual values, all pairing counts, code, figures, and checks.

California · precipitation · spring recovery · seasonal dependence · rare events · bootstrap boundary · nClimDiv